Development of a serial powering scheme and a versatile characterization system for the ATLAS pixel detector upgrade

In order to increase the probability of new discoveries the LHC will be upgraded to the HL-LHC. The upgrade of the ATLAS detector is an essential part of this program. The entire ATLAS tracking system will be replaced by an all-silicon detector called Inner Tracker (ITk) which should be able to withstand the increased luminosity. The work presented in this thesis is focused on the ATLAS ITk pixel detector upgrade. Advanced silicon pixel detectors will be an essential part of the ITk pixel detector where they will be used for tracking and vertexing. Characterization of the pixel detectors is one of the required tasks for a successful ATLAS tracker upgrade. Therefore, the work presented in this thesis includes the development of a versatile and modular test system for advanced silicon pixel detectors for the HL-LHC. The performance of the system is verified. Single and quad FE-I4 modules functionalities are characterized with the developed system. The reduction of the material budget of the ATLAS ITk pixel detector is essential for a successful operation at high luminosity. Therefore, a low mass, efficient power distribution scheme to power detector modules (serial powering scheme) is investigated as well in the framework of this thesis. A serially powered pixel detector prototype is built with all the components that are needed for current distribution, data transmission, sensor biasing, bypassing and redundancy in order to prove the feasibility of implementing the serial powering scheme in the ITk. Detailed investigations of the electrical performance of the detector prototype equipped with FE-I4 quad modules are made with the help of the developed readout system

Design and Implementation of a High-Speed Readout and Control System for a Digital Tracking Calorimeter for proton CT

Particle therapy, a non-invasive technique for treating cancer using protons and light ions, has become more and more common. For example, a particle treatment facility is currently being built, in Bergen, Norway. Proton beams deposit a large fraction of their energy at the end of their paths, i.e., the delivered dose can be focused on the tumor, sparing nearby tissue with a low entry and almost no exit dose. A novel imaging modality using protons promises to overcome some limitations of particle therapy and allowing to fully exploit its potential. Being able to position the so-called Bragg peak accurately inside the tumor is a major advantage of charged particles, but incomplete knowledge about a crucial tissue property, the stopping power, limits its precision. A proton CT scanner provides direct information about the stopping power. It has the potential to reduce range uncertainties significantly, but no proton CT system has yet been shown to be suitable for clinical use. The aim of the Bergen proton CT project is to design and build a proton CT scanner that overcomes most of the critical limitations of the currently existing prototypes and which can be operated in clinical settings. A proton CT prototype, the Digital Tracking Calorimeter, is being developed as a range telescope consisting of high-granularity pixel sensors. The prototype is a combined position-sensitive detector and residual energy-range detector which will allow a substantial rate of protons, speeding up the imaging process. The detector is single-sided, meaning that it employs information from the beam delivery system to omit tracker layers in front of the phantom. The detector operates by tracking the charged particles traversing through the detector material behind the phantom. The proton CT prototype will be used to determine the feasibility of using proton CT to increase the dose planning accuracy for particle treatment of cancer cells. The detector is designed as a telescope of 43 layers of sensors, where the two front layers act as the position-sensitive detector providing an accurate vector of each incoming particle. The remaining layers are used to measure the residual energy of each particle by observing in which layer they stop and by using the cluster size in each layer. The Digital Tracking Calorimeter employs the ALPIDE sensor, a monolithic active pixel sensor, each utilizing a 1.2Gb/s data link. Each layer of 18×27 cm consists of 108 ALPIDE sensors, roughly corresponding to the width and height of the head of a grown person. The sensors are connected to intermediary transition boards that route the data and control links to dedicated readout electronics and supply the sensors with power. The readout unit is the main component of both the data acquisition and the detector control system. The power control unit controls the power supply and monitors the current usage of the sensors. Both of these devices are mainly implemented in FPGAs. The main purpose of this work has been to explore and implement possible design solutions for the proton CT electronics, including the front-end, as well as the readout electronics architecture. The resulting architecture is modular, allowing the further scale-up of the system in the future. A major obstacle to the design is the high amount of sensors and the corresponding high-speed data links. Thus, a large emphasis has been on the signal integrity of the front-end electronics and a dynamic phase alignment sampling method of the readout electronics firmware. The readout FPGA employs regular I/O pins for the high-speed data interface, instead of high-speed transceiver pins, which significantly reduces the magnitude of the data acquisition system. A consistent design approach with detailed and systematic verification of the FPGA firmware modules, along with a continuous integration build system, has resulted in a stable and highly adaptive system. Significant effort has been put into the testing of the various system components. This also includes the design and implementation of a set of production test tools for use during the manufacturing of the detector front-end.Doktorgradsavhandlin

Research Proposal for an Experiment to Search for the Decay {\mu} -> eee

We propose an experiment (Mu3e) to search for the lepton flavour violating decay mu+ -> e+e-e+. We aim for an ultimate sensitivity of one in 10^16 mu-decays, four orders of magnitude better than previous searches. This sensitivity is made possible by exploiting modern silicon pixel detectors providing high spatial resolution and hodoscopes using scintillating fibres and tiles providing precise timing information at high particle rates.Comment: Research proposal submitted to the Paul Scherrer Institute Research Committee for Particle Physics at the Ring Cyclotron, 104 page

Belle II Technical Design Report

The Belle detector at the KEKB electron-positron collider has collected almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an upgrade of KEKB is under construction, to increase the luminosity by two orders of magnitude during a three-year shutdown, with an ultimate goal of 8E35 /cm^2 /s luminosity. To exploit the increased luminosity, an upgrade of the Belle detector has been proposed. A new international collaboration Belle-II, is being formed. The Technical Design Report presents physics motivation, basic methods of the accelerator upgrade, as well as key improvements of the detector.Comment: Edited by: Z. Dole\v{z}al and S. Un

Power and Monitor Solution for the Proton Computed Tomography Project

The ProtonCT project is an academic endeavor carried out by the University of Bergen in collaboration with several universities and entities across the world. The end goal of the project is to improve dosage plans by directly measuring the relative stopping power of protons using a digital tracking calorimeter. Directly measuring relative stopping power as opposed to approximating it using CT numbers can provide a more accurate dosage plan. The digital tracking calorimeter will be able to do computed tomography scans of head-sized objects. The digital tracking calorimeter will utilize pixel detector sensors developed by CERN for the ALICE project. 43 pixel arrays, segmented into layers, measure the angle and energy of proton particles traversing through the layers. With 108 chips per layer, 4644 ALPIDE chips build up all the layers. At full load, the expected power draw is close to 2.5kW. This thesis explores the design of a user-controllable power delivery and monitoring system. Each layer consists of 12 ALPIDE strings, with 9 ALPIDE chips making up one string. A power delivery system capable of supplying one layer is realized by using a small form factor switch mode power supply unit. An FPGA design created by peer students connects the 43 power delivery systems to a graphical interface. A filter, monitor, and control solution is designed with a newly released AVR microcontroller unit. A custom PCB, named the Monitor Board, is designed to host the filter and the MCU with all its support circuitry. Using differential signaling, the 43 monitorboards communicate with a Xilinx Kintex UltraScale FPGA responsible for storing and relaying information over IPbus to the user. Each monitor board can switch the strings of its designated layer on or off. Diagnostics and soft startups/shutdowns can be executed through software. The back-biasing of an entire layer is customizable by using the microcontroller DAC and an onboard negative voltage supply. A temperature monitoring solution is designed with the use of a PT1000 element mounted close to the ALPIDE chips.Master's Thesis in PhysicsPHYS399MAMN-PHY

Technical Design Report for the PANDA Micro Vertex Detector

This document illustrates the technical layout and the expected performance of the Micro Vertex Detector (MVD) of the PANDA experiment. The MVD will detect charged particles as close as possible to the interaction zone. Design criteria and the optimisation process as well as the technical solutions chosen are discussed and the results of this process are subjected to extensive Monte Carlo physics studies. The route towards realisation of the detector is outlined

The ATLAS experiment at the CERN Large Hadron Collider: a description of the detector configuration for Run 3

The ATLAS detector is installed in its experimental cavern at Point 1 of the CERN Large Hadron Collider. During Run 2 of the LHC, a luminosity of ℒ = 2 × 1034 cm-2 s-1 was routinely achieved at the start of fills, twice the design luminosity. For Run 3, accelerator improvements, notably luminosity levelling, allow sustained running at an instantaneous luminosity of ℒ = 2 × 1034 cm-2 s-1, with an average of up to 60 interactions per bunch crossing. The ATLAS detector has been upgraded to recover Run 1 single-lepton trigger thresholds while operating comfortably under Run 3 sustained pileup conditions. A fourth pixel layer 3.3 cm from the beam axis was added before Run 2 to improve vertex reconstruction and b-tagging performance. New Liquid Argon Calorimeter digital trigger electronics, with corresponding upgrades to the Trigger and Data Acquisition system, take advantage of a factor of 10 finer granularity to improve triggering on electrons, photons, taus, and hadronic signatures through increased pileup rejection. The inner muon endcap wheels were replaced by New Small Wheels with Micromegas and small-strip Thin Gap Chamber detectors, providing both precision tracking and Level-1 Muon trigger functionality. Trigger coverage of the inner barrel muon layer near one endcap region was augmented with modules integrating new thin-gap resistive plate chambers and smaller-diameter drift-tube chambers. Tile Calorimeter scintillation counters were added to improve electron energy resolution and background rejection. Upgrades to Minimum Bias Trigger Scintillators and Forward Detectors improve luminosity monitoring and enable total proton-proton cross section, diffractive physics, and heavy ion measurements. These upgrades are all compatible with operation in the much harsher environment anticipated after the High-Luminosity upgrade of the LHC and are the first steps towards preparing ATLAS for the High-Luminosity upgrade of the LHC. This paper describes the Run 3 configuration of the ATLAS detector

Development of electronics for the VELO upgrade detector

Esta tesis cubre el diseño electrónico del detector de vértices (VELO) del experimento LHCb del CERN. El VELO está situado rodeando el punto de colisión de los dos haces de protones del LHC del CERN. Su diseño está lleno de restricciones que requieren diseños novedosos: minimizar la materia cerca del punto de colisión, diseño de componentes que soporten radiación, transmisión de datos a alta tasa y el procesado de los mismos, sincronización del sistema, etc. El trabajo presentado en esta tesis se centra en: por un lado, la validación del hardware y sus diferentes prototipos, por otro lado, el diseño del firmware de las FPGAs encargadas del control, sincronización y adquisición de datos del VELO

High-Speed Signal and Power Distribution of a Digital Tracking Calorimeter for Proton Computed Tomography

Masteroppgave i fysikkPHYS399MAMN-PHY